DE1643497C3 - Process for the production of glycidyl ethers of monohydric and polyhydric phenols - Google Patents

Description

Glycidyl ether of mono- or polyhydric phenols represents jo is known to be produced in that the phenolic OH group-containing compounds are present in the presence of alkali reacts with epichlorohydrin proceed so that for the preparation of solid glycidyl ethers per phenolic OH group 1 - 2 moles of epichloro hydrin and, for the production of low molecular weight, liquid glycidyl ethers, 3–20 mol epichlorohydrin per phenolic OH group

The alkali metal chloride formed during the reaction can can be removed as a by-product by various methods. According to the German interpretative document 10 81 666 described method takes the preparation of the liquid glycidyl ethers to the exclusion of water before. Such a process has the disadvantage that initially the alkali salt of the one or 4> polyhydric phenols must be produced in dry form. Also, the recovery is not converted phenolate from the alkali metal chloride formed in the reaction with epichlorohydrin is cumbersome. The glycidyl ethers are relatively highly viscous and do not meet the technical requirements due to their high chlorine content.

In the known processes (compare German Patent 10 16 273), where in the presence is worked by water, one can proceed in such a way that either one in a solution containing 1 mole of the or polyhydric phenols in 3–10 moles of epichlorohydrin per phenolic OH group, below Reflux adds solid alkali in portions or an at least 15% aqueous alkali solution, the Tem = m> adjusts the temperature of the reaction mixture so that it contains only 0.3-2% by weight of water and the remainder Water distilled off azeotropically together with epichlorohydrin. The alkali chloride formed in the reaction is removed by filtration after removing the excess epichlorohydrin and taking up the residue in a suitable solvent. These Process have the disadvantage that through contact undesirable side reactions of the hot epichlorohydrin with the alkali at the relatively high temperature occur that lead to epichlorohydrin losses, to glycidyl ethers with relatively high viscosities and to gelling Lead resin proportions. A further loss of epichlorohydrin occurs because the azeotropically separated off Water contains 5-10% by weight epichlorohydrin which would be costly to recover from the water. the Glycidyl ethers are also relatively highly viscous. The average chlorine content is 0.5% by weight.

According to another known method, which is described in the German Auslegeschrift 11 31 413 is, and which is to be carried out mainly continuously, is in the presence of ketones with up to worked to 4 carbon atoms This process has the disadvantage that with the separated aqueous phase a lot of ketone is lost, the recovery of which makes the process more expensive. In addition, resins are also obtained a relatively high viscosity and high total chlorine content

According to the procedure which is given in the German Auslegeschrift 11 28 667, the alkali is in dissolved a lower alcohol and then slowly dissolve the polyhydric phenol in one Given epihalohydrin. After the completion of the reaction, there will be excess epihalohydrin and the alcohol is distilled off together on an industrial scale, since the water of reaction accumulates in the distillate and is used to produce the alcoholic alkali solution only low molecular weight, water-soluble alcohols are suitable. Glycidyl ethers of bisphenol A produced by this process show high viscosities and chlorine levels.

In US Pat. No. 28 48 435, the production of glycidyl ethers in the presence of a secondary monohydric alcohol, especially selc-butanol, is published, compared to the use of primary Alcohols, such as ethyl or isopropyl alcohol, the advantage should be that there is less loss of epichlorohydrin due to the formation of glycidyl ethers from the corresponding alcohols should arise. According to this process, only relatively highly viscous glycidyl ethers are obtained in unsatisfactory yield.

It can be seen from the examples of the US patent that the alcohol must be used in an amount of about 20 to 200% based on the corresponding weight of epichlorohydrin. In order to raise glycidyl ethers of low viscosity, the process requires a high excess of epichlorohydrin in the range of 10 to 2%. Moles based on 1 mole of bisphenol A can be used. The chlorine contents of the glycidyl ethers produced by this process are on average over 0.5% by weight.

The invention was based on the object of producing glycidyl ethers of mono- or polyhydric phenols by reacting the phenolic OH group with excess Epichlorohydrin in the presence of alkali in very pure form with good yield and high conversions in the To obtain time units that are of low viscosity «have a low epoxy equivalent and only a low chlorine content, and have high viscosity stability (measured in accordance with DIN 16 945 4.2).

The invention relates to a process for the production of low-viscosity liquid glycidyl ethers monohydric or polyhydric phenols by reacting a monohydric or polyhydric phenol with 3 to 15 moles of epichlorohydrin per phenolic hydroxyl group and

mindestem ⁵ 98 wt .-% of the phenolic hydroxyl equivalent amount of alkali metal or alkaline earth metal hydroxide in the presence of a limited water-soluble aliphatic alcohol at temperatures of 60 to 100 ⁰ C, recovering the formed polyglycidyl ithers by distilling off the excess epichlorohydrin, the limited water-soluble alcohol and of the water of reaction formed from the reaction mixture and separation of the alkali or alkaline earth chloride, which is characterized in that the reaction is carried out at temperatures of 75-95 ° C in the presence of 5-10 wt .-% of the limited water-soluble aliphatic alcohol, based on the amount of epichlorohydrin used, using 98 to 105% by weight of the amount of solid alkali metal or alkaline earth metal hydroxide equivalent to the phenolic hydroxyl groups

The following can be used as mono- or polyhydric phenols: phenol, o-, m- and p-cresol, 1,2,4-, 1,2,6-, 1,2,3-, 1,2,5-, 13,4- and 13,5-xylenol, p-tert-butylphcno'i, o-, m- and p-pheny! Pheno !, the isomeric amylphenols, octylphenols and monylphenols, resorcinol, hydroquinone, 1,4-dihydroxynaphthalene and other dihydroxynaphthalenes, 4,4'-dihydroxydiphenyl, 2,2'-dihydroxydiphenyl, and other isomeric dihydroxydiphenyls; 4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxydbenzyl, also substituted dihydroxydiphenylmethanes, which are formed by the acidic condensation of phenols with aldehydes or ketones, in particular 4,4'-dihydroxydiphenyl-2,2-propane, which can be prepared from phenol and acetone, the so-called diphenylolpropane or bisphenol A, also dihydroxydiphenylcyclohexane. Further examples are:

4,4'-dihydroxy-3,3 ', 5,5'-tetramethyl- { _i .phenyl-

methane, 4,4'-dihydroxy-3,3 ', 5,5'-tetramethyl-diphenyl-

2,2-propane, 4,4'-dihydroxy-3,3 ', 5,5'-tetra-tert-butyl-

diphenyl methane, 4,4'-dihydroxy-3,3 ', 5 _I 5'-tetra-tert-butyl-

diphenyl-2,2-propane, 4,4'-dihydroxy-3,3'-dimethyl-5,5'-di-tert-

butyl-diphenyl-methane, 4,4'-dihydroxy-3,3'-dimethyl-5,5'-d! -Tert-

butyl-diphenyl-2,2-propane, 4,4'-dihydroxy-3,3 \ 5,5'-tetraamyl-diphenyI-

cyclohexane, 4,4'-dihydroxy-3,3 ', 5,5'-tetra-tert-butyI-

diphenylcyclohexane and 4,4'-dihydroxy-3 _r 3'-dimethyl-5,5'-di-tert.-

butyl-diphenylcyclohexane.

The polyhydric phenols used as starting materials can, in addition to the phenolic hydroxyl groups, also contain other substituents or functional groups in the molecule, e.g. B. hydrocarbon residues, ether groups, ester groups, halogen atoms, hydroxyl groups and others, provided that the reaction is not disturbed. To come after in question:

4,4'-dihydroxydiphenyl sulfone,

Tetrabromobisphenol, Tetrachlorobisphenol, Chlorohydroquinones, Methylresorcinol and Phloroglucine.

There are also polyhydric phenols, e.g. novolak resins, the acid-catalyzed condensation of phenol, p-cresol or other substituted phenols with aldehydes such as formaldehyde, acetaldehyde, crotonaldehyde, are obtained, condensates of phenols with cardanol, as in US Pat. No. 23 17 607 indicated, condensates of phenols with aliphatic diols, as described in US Pat. No. 23 21 620, and condensates of phenols with un-

saturated fatty oils as published in US Pat. No. 2,031,586 in question.

The above list of the starting materials appropriate connections is not exhaustive. A detailed compilation of the comrcen in question the connections is z. B. in the book »Epoxydver- bonds and epoxy resins «by A. M. P; i q u i η, Springer-Verlag, 1958, pages 256-307.

Phenol, p-tert-butylphenol, ice phenol A and tetrabromobisphenol are preferably used

The alkali or alkaline earth hydroxides are used solid compounds in granular or powdered form are possible, with sodium hydroxide being preferred Alkali hydroxide is used in the reaction 3-15, preferably 5-8 moles of epichlorohydrin per phenoli shear OH group. Use 5-10% by weight, based on the amount of epichlorohydrin used, of an alcohol with limited water solubility, such as n-butanol, i-butanol, sele-butyl alcohol, the various isomeric pentanols or hexanols, preferably

to i-butanol or n-butanol. The implementation is in Presence of 98-105% by weight of the phenolic Hydroxyl group equivalent amount of solid alkali metal hydroxide or alkaline earth metal hydroxide, the portionwise is added at 75-95 ° C, under normal pressure or carried out under reduced pressure. After the addition of the alkali or alkaline earth metal hydroxide, the reaction is allowed to subside at about 80-90 ° C. in about 30 minutes. Is distilled under reduced pressure at a temperature of 60-70 ⁰ C again as much over Schüssiges epichlorohydrin from that the Reak formed tion water is removed from the batch, then filtered off the metal halide formed in the reaction and further constricts under vacuum and heating the batch to 120 ° C. The liquid resin can be removed filter again to remove minor impurities. Or the excess epichlorohydrin, the alcohol with limited water solubility and the water of reaction are removed under vacuum at temperatures of initially 60 ^° C. and finally 120 ^{° C.} Reaction product in a suitable solvent such as acetone, methyl isobutyl ketone, benzene, or toluene Xylene, and washes off the alkali chloride with water. The resin solution is dehydrated by azeotropic distillation, finally under normal pressure and / or Reduced vacuum. The liquid glycidyl ether can can then be freed from impurities by filtration. The new process is characterized by the fact that, firstly, the yield is almost that of the Theory according to the resulting amount of glycidyl ether ent speaks and secondly, since during the actual Kon densation, neither azeotropic dehydration is necessary, nor is a larger aqueous phase present Epichlorohydrin losses are extremely low. It also reduces the secondary epichlorohydrin losses by undesired side reactions such as polymerisation of epichlorohydrin or ether formation Epichlorohydrin and the limited water-soluble alcohol in the presence of alkali by the applied

lower reaction temperature of 75-95 ⁰ C to a minimum depressed which is obtained after the Glycjdyläther-Bjldung The distillate, in addition to excess epichlorohydrin and the limited water-soluble alcohol contains only the small amount of water of reaction, which partially separates into a top layer and is removed . The organic distillate can be used for the next batch after supplementing with epichlorohydrin and the small proportion of the alcohol which has limited water solubility and which has been lost with the aqueous phase. Another technical advantage of the glycidyl ethers produced by this process is their high viscosity stability (measured in accordance with DIN 16 945, 4.2), as will be shown by giving comparative measurement data. To improve the dissolution of the Alkalibzw. Alkaline earth hydroxide can be added to the reaction mixture from 0.2 to 5% by weight of water.

example 1

1205 g epichlorohydrin,

84 g n-butanol,
2 g water and

330 g bisphenol A

were brought to 85 ° C. in a three-necked flask equipped with a thermometer, stirrer and reflux condenser held.

At this temperature 120 g of solid sodium hydroxide were added in 30-45 minutes. After the addition had ended, the mixture was ^{held at 90 °} C. for a further 30 minutes. Destillattonsvorlage a vacuum was then applied and after installation gently at 60-80 ⁰ C distilled 342 g of distillate. After cooling to 30-50 ° C., it was filtered. The clear solution was further concentrated under vacuum in the cleaned flask, at temperatures up to 150 ° C. At 150 ° C., the mixture was kept under full vacuum for a further 2 hours. After cooling to 100 ° C., the mixture was dissolved in 350 g of xylene and, after addition of 3 g of kieselguhr, it was filtered. Then xylene was distilled off in vacuo, at a temperature of up to 150 ° C. At 150 ° C, the mixture is again kept under full vacuum for 2 hours. 476 g of the polyglycidyl ether of bisphenol A are obtained with an epoxide equivalent of 186 and a Hoppler viscosity, measured at 25 ° C., of 9.28 Pa s. The total chlorine content is 0.26% by weight.

Example 2

1200 g epichlorohydrin,

85 g isobulanol,
2 g water and

330 g bisphenol A

were heated to 85 ° C. in the same manner as described in Example 1. 120 g of solid sodium hydroxide were added in the same way. However, it was removed after completion of the reaction under reduced pressure at temperatures of 60 ⁰ C initially and finally 12O ° C excess Epichlorbydrin, i-butanol and water of reaction. At 120 ^° C., the mixture was kept under full vacuum for a further hour. The glycidyl ether was then taken up in 500 g of methyl isobutyl ketone and the sodium chloride was washed out of the resin solution twice with 660 g of water. The solvent was then removed and the liquid glycidyl ether

ίο filtered 470 g of the liquid polyglycidyl ether were obtained with an epoxy equivalent of 190 and a Höppler viscosity of 7.6 Pa s. The total chlorine content is 0.25 wt%.

comparison

The same experiment as in Example 2 is carried out, but in the absence of i-butanol.

A polyglycidyl ether with an epoxy equivalent of 192 and a Höppler viscosity is obtained : <> measure at 25 ° C, of 19.0 Pas, which is proven that low viscosity resins are obtained in the process according to the invention.

Example 3

r> Mar: carried out the same experiment as in Example 2, but instead of 1200 g of epichlorohydrin, 1600 g of epichlorohydrin.

473 g of the polyglycidyl ether with an epoxide equivalent of 185 and a Hoppler viscosity were obtained

measured at 25 ° C, of 8.94 Pa s. The total chlorine content is 0.27% by weight.

Example 4

The experiment according to Example 2 was carried out. Man

r, but used the distillate from Example 2, which had been freed from the small aqueous phase, which was approx.

1000 g and supplemented it with 305 g of epichlorohydrin and 4 g of isobutanol.

A polyglycidyl ether with an epoxy equivalent of 195 and a Höppler viscosity was obtained measured at 25 ° C, of 14.5 Pa s. The total chlorine content is 0.24 wt%.

Example 5

4 ", The same experiment as in Example 2 was carried out through, but instead of bisphenol A, 477 g of p-tert-butylphenol were used.

630 g of the liquid glycidyl ether with an epoxide equivalent of 230 and a Höppler

5n viscosity of 18 · 10 " ³ Pas, measured at 25 ° C. The total chlorine content is 0.28% by weight.

The following table shows the viscosity stability of the method of the present invention produced various polyglycidyl ethers,

5ϊ measure specified in accordance with DIN 16 945.4.2.

Tabel

Manufactured according to the invention according to Example I, Example 2

Example 3

Initial viscosity at 120 ° C
Viscosity after 24 h / 120 ° C
increase
Increase in%

14.65 ■ 10- ^J Pas 14.72 ■ 10-'Pa s 0.07 · 10- ^J Pas 00:48

14.31 x 10- ^J Pas
14.39 · 10-3 Pa s
0.08 x 10- ^J Pas
0.56

12.09 x 10-'Pa s
12.18 · 10 ^-3 Pas
0.09 · 10 ^-3 Pas
0.75

Manufactured according to the invention according to Example 4 Example 6

More commercially available Polyglycidyl ether

More commercially available Polyglycidyl ether

Initial viscosity at 120 "C 15.22 • 10 JPas 13.91 ■ ΙΟ- ³ Pa s 15.41 • 10-3 Pa s 14.51 • 10-3 Pa s Viscosity after 24 h / 120 ° C 1532 • 10-3 Pa s 13.97 • ΙΟ- ³ Pa s 15.81 • 10-3 Pa s 15.78 • 10-3Pas increase 0.10 10-3 Pa s increase 0.10 ΙΟ- ³ Pa s 0.06 10-3Pas 0.4 ΙΟ- ¹ Pa s 0.27 ΙΟ- ³ Pa s Increase in% 0.65 0.43 2.6 1.86

The table shows that the polyglycidyl ethers, the were produced by the method according to the invention, compared to the comparison products by a Characterized by a lower increase in viscosity, which speaks for the greater purity of the products. This is before especially important for the use of these polyglycidyl ethers in the electrical sector. Otherwise there is no such purity can only be achieved by the expensive route of molecular distillation of polyglycidyl ethers.

Example 6

The same experiment was carried out as in Example 2, but without the addition of the 2 g of water.

469 g of the polyglycidyl ether were obtained with an epoxide equivalent of 186 and a viscosity, measured at 125 ° C, of 12.1 Pas. The total chlorine content is 0.24 wt%.

Example 7

The same experiment was carried out as in Example 2, but instead of 85 g of isobutanoi, 85 g of a mixture of isomeric pentyl alcohols with boiling points at 1.013 bar of 137-144 ° C. were used; the density was added at 90 ° C. for a further 30 minutes held. Then cho '/ A · of 0.847 and the refractive index npxr, of 1.4210.

480 g of polyglycidyl ether of bisphenol A with an epoxide equivalent of 190, a Hoppler viscosity, were obtained measured at 25 ° C., 10.9 Pa s and a total chlorine content of 03% by weight.

Example 8

216 g of tetrabromobisphenol, 147 g of bisphenol, 980 g of epichlorohydrin and 85 g of isobutanoi were kept at 85 ° C. in a three-necked flask equipped with a thermometer, stirrer and reflux condenser. At this temperature, 83 g of solid sodium hydroxide were added in portions over a period of 2.5 hours. After the addition had ended, the mixture was held at 90 ° C. for a further 30 minutes. A vacuum distillation receiver was then carefully applied after installation and excess under reduced pressure at temperatures of initially 60 ° C and finally 120 ⁰ C epichlorohydrin, Isobutanoi and water of reaction removed at 120 "C is held for one hour full vacuum (about 0.96 to 1 bar) upright The mixture was then allowed to cool to 100 ° C., and the vacuum was released by introducing CO ₂ . The residue in the flask was dissolved in 520 g of xylene, and 390 g of H2O were added. The H2O was stirred for 10 min at 90 ° C. in order to dissolve the precipitated common salt. The aqueous phase was then separated off, the xylene solution was dehydrated in the circuit with return of the xylene to the flask, removed after de;

ii Circulation drainage another 50 g of xylene and filtered the resin solution. Subsequently, the Htirzlösung in a clean flask was removed by vacuum distillation of xylene, last hei 150 ⁰ C. unier einfim vacuum from 0.96 to 1 bar, the held for 2 hours erect

2n was.

Man ernicit a viscous epoxy resin with a Epoxy equivalent 255 and a Höppler viscosity, measured at 25 ° C., of 90 Pa s, that for flame-resistant Einbi itngen and coatings is suitable.

Example 9

üOOO kr? Epichlorohydrin,
425 kg of isobutanoi and
1650 kg bisphenol

jo were in a reaction vessel made of stainless steel material, which is provided with indirect heating, cooling jacket, agitator and a distillation device Heated to 85 ° C. A rotary valve was used to add 600 kg of caustic soda in 2.5 hours. To the Dissipation of the heat of reaction was cooled and, moreover, a more or less strong circulation distillation carried out at 85-90 ° C and 0.66 to 0.79 bar with recycling of the distillate. After completion the addition of caustic soda was continued as described in Example 2. 2370 kg of liquid were obtained Polyglycidyl ether with an epoxy equivalent of 189 and a Höppler viscosity measured at 25 ° C, of 9.300 Pa s. The total chlorine content is 0.23% by weight.

45

Example 10

1265 g of a technical epichlorohydrin, which contains approx.

Contained 5% by weight xylene,
85 g isobutanoi and
330 g bisphenol A

were according to the specifications made in Example 2 to react and worked 465 g of polyglycidyl ether obtained had an epoxy equivalent of 191 and a Hoppler viscosity as measured at 25 ⁰ C, of 103 Pa s. The viscosity increase after 24 hours of storage at 120 ° C was 0 , 63%. The total chlorine content was 0.24% by weight.

50

Claims (1)

Claim: Process for the production of low viscosity liquid glycidyl ethers of monohydric or polyhydric phenols by reacting a monohydric or polyhydric phenol with 3 to! 5 moles of epichlorohydrin per phenolic hydroxyl group and at least 98% by weight of the amount of alkali metal or alkaline earth metal hydroxide equivalent to the phenolic hydroxyl groups in the presence a limited water-soluble aliphatic alcohol at temperatures of 60 to 100 ⁰ C, recovery of the polyglycidyl ether formed by distilling off the excess epichlorohydrin, the limited water-soluble alcohol and the water of reaction formed from the reaction mixture and separation of the alkali. Alkaline earth chloride, characterized in that the reaction is carried out at temperatures of 75-95 ° C in the presence of 5-10% by weight of the aliphatic alcohol with limited water solubility, based on the amount of epichlorohydrin used, using 98 to 105% by weight b the amount of solid alkali metal or alkaline earth metal hydroxide equivalent to the phenolic hydroxyl groups